NEW YORK (Reuters Health) - Imaging with gallium-68
DOTATATE positron emission tomography (PET) and computed
tomography (CT) offers advantages over other methods of
detecting gastro-entero-pancreatic neuroendocrine tumors
(GEPNETs), according to researchers at the National Institutes
of Health.

In a December 28 online paper in the Journal of Clinical
Oncology, Dr. Electron Kebebew, of the National Cancer
Institute, Bethesda, Maryland, and colleagues note that the
approach is still investigational and "there have been no large
prospective studies with comprehensive biochemical screening to
evaluate its clinical utility when specifically focused on
GEPNETs."

To do so, the team enrolled 131 patients with suspected or
known GEPNETs who underwent 68Ga-DOTATATE imaging. They compared
that with current Food and Drug Administration-approved imaging
modalities, 111In-pentetreotide single-photon emission computed
tomography (SPECT/CT), CT, and/or magnetic resonance imaging
(MRI).

In four of 14 patients, compared to histopathology,
proportions for correct detection of a previously unknown
primary tumor, primary GEPNET, lymph node, and distant
metastases were 63.7% for 68Ga-DOTATATE PET/CT compared to 22.1%
for 111In-pentetreotide SPECT/CT and 38.9% with anatomic
imaging.

Because of these findings, say the investigators, 43 of the
patients (32.8%) had a change in management recommendation.
Moreover, in patients with carcinoid symptoms but negative
biochemical testing, 68Ga-DOTATATE PET/CT detected lesions in
65.2%. Of these, 40% were detected neither by anatomic imaging
nor by 111In-pentetreotide SPECT/CT.

Among limitations of the study, say the investigators, is
that "we do not have histopathologic proof for every lesion
detected; thus, false positive results are possible." Also it is
not known whether "the therapeutic options selected on the basis
of 68Ga-DOTATATE PET/CT imaging resulted in improved long-term
patient outcome."

However, the researchers conclude that the approach is more
sensitive for staging and detecting unknown primary GEPNETs than
are the others and that "it should be implemented in the initial
management and follow-up of patients with GEPNETs as it can
significantly optimize patient care decisions."

Commenting on the findings by email, Dr. Ebrahim S.
Delpassand, chairman and medical director at Excel Diagnostics
and Nuclear Oncology Center, Houston, Texas, told Reuters Health
"This is a nicely written manuscript by our colleagues at NIH on
an important test for patients with NET."

"The results match other previously published literature on
this topic," and he concluded, "This test will be a new gold
standard for diagnostic management of patients with NET."